How much does BBC reporter John Sweeney discover from inside the secretive state that isn't already known?

"'Journalists are all but banned from North Korea, so I'm going in undercover," says John Sweeney. I think he quite likes saying that. He is of course with a group of LSE students on a study trip, pretending to be a history teacher. He looks the part too. Don't forget they don't really have the internet in North Korea, so they won't have seen his famous Scientology rant on YouTube."

Description: The Guardian's TV reviewer Sam Wollaston discusses the broadcast of Panorama's North Korea undercover story, a story that has caused an uproar for allegedly endangering students.